This invention relates generally to gas generant materials and, more particularly, to high gas yield generant compositions such as may be suited for use in inflating automotive inflatable restraint airbag cushions.
It is well known to protect a vehicle occupant using a cushion or bag, e.g., an "airbag cushion," that is inflated or expanded with gas when the vehicle encounters sudden deceleration, such as in the event of a collision. In such systems, the airbag cushion is normally housed in an uninflated and folded condition to minimize space requirements. Upon actuation of the system, the cushion begins to be inflated, in a matter of no more than a few milliseconds, with gas produced or supplied by a device commonly referred to as "an inflator."
While many types of inflator devices have been disclosed in the art for use in the inflating of one or more inflatable restraint system airbag cushions, inflator devices which rely on the combustion of a pyrotechnic, fuel and oxidizer combination or other form of gas generant to produce or at least in part form the inflation gas issuing forth therefrom have been commonly employed in conjunction with vehicular inflatable restraint airbag cushions.
At the present time, sodium azide is a commonly accepted and used gas generating material. While the use of sodium azide and certain other azide-based gas generant materials meets current industry specifications, guidelines and standards, such use may involve or raise potential concerns such as involving handling, supply and disposal of such materials.
In addition, economic and design considerations have also resulted in a need and desire for alternatives to azide-based pyrotechnics and related gas generants. For example, interest in minimizing or at least reducing overall space requirements for inflatable restraint systems and particularly such requirements related to the inflator component of such systems has stimulated a quest for gas generant materials which provide relatively higher gas yields per unit volume as compared to typical or usual azide-based gas generants. Further, automotive and airbag industry competition has generally lead to a desire for gas generant compositions which satisfy one or more conditions such as being composed of or utilizing less costly ingredients or materials and being amenable to processing via more efficient or less costly gas generant processing techniques.
As a result, the development and use of other suitable gas generant materials has been pursued. Thus, efforts have been directed to the development of azide-free pyrotechnics for use in such inflator device applications. In particular, there is a need and a desire for an azide-free gas generant material that, while overcoming at least some of the potential problems or shortcomings of azide-based gas generants, may also provide relatively high gas yields, such as compared to typical azide-based gas generants. In particular, relatively low cost gas generant material solutions to one or more such problems or limitations are desired.